There are various types of mobile devices which are used for handling, or manipulating heavy loads. Many of them, like hydraulic excavators, have a chassis on which a boom member is pivotally mounted, there is an arm member pivoted at the free end of the boom, and an excavator bucket or other hydraulically operated apparatus is at the free end of the arm. Hydraulically operated mechanisms mounted on such devices in place of excavator buckets include tree harvesting devices, log grapples, hydraulic impact hammers, pile drivers or earth compactors, etc. Hydraulic conduits must be mounted on the boom and the arm.
The booms of such devices have hydraulic cylinders at their two sides to pivot the boom relative to the chassis, and problems of manufacturing tolerances and operating conditions require that the hydraulic cylinders be mounted on the chassis on spherical mounting joints and that the piston rods of the cylinders be operatively attached to the sides of the boom by spherical connecting joints. The cylinders and the hydraulic fluid conduits connected to their head ends and their rod ends are exposed to substantial risk of damaging impact in the rough environments in which the devices are used, so a guard structure is essential, particularly for the conduits and conduit couplings.
The entire guard structure must be mounted upon the two hydraulic cylinders, and the axial rotation of the cylinders relative to one another makes it difficult to develop a satisfactory mounting for the guard structure. The problem is complicated by the fact that a single cylinder for moving the arm on the end of the boom has its flexible hydraulic conduits extending along the underside of the boom, and the guard for the boom cylinder conduits must not interfere with free movement of the flexible conduits for the arm.
In the prior art known to applicant, the boom cylinder conduit guard has been fabricated from a pliable material, such as heavy sheet rubber. Such guards are expensive, and not particularly satisfactory because the sheet rubber can be relatively easily torn or ruptured.